The demo version of Left 4 Dead 2 will become available for gameplay on October 27th…for those people lucky enough to have pre-ordered the zombie game.

According to Valve Software, people who have pre-ordered Left 4 Dead 2 using the Steam client (like this eager Zombiephile) are currently able to pre-load the game demo, making it available for instant access on Tuesday, October 27. The early access for the Left 4 Dead 2 demo is available to both XBox 360 and PC pre-orders, in addition to pre-orders through the PC Steam client. If you’ve pre-ordered through the PC Steam client, you should be able to login right now and begin pre-loading the demo immediately (mine finished downloading last night); however, if you’ve pre-ordered from a retail store, you will have to visit participating retailers to pick up an early access code, which you can do this weekend.

The demo will not feature all new weapons and levels, but Valve has confirmed that it will feature the new baseball bat melee weapon, and will be multiplayer, meaning that you’ll be able to share your reactions to the new Left 4 Dead 2 Demo with other players around the world.

How awesome is it that this Zombiephile is going to be able to bring you a review of Left 4 Dead 2 on Tuesday? Pretty awesome, as far as I’m concerned. Of course, I’ll have to tear myself away from the zombie game long enough to write the actual review, so don’t be shocked or heartbroken if the Left 4 Dead 2 Demo review doesn’t actually appear until Wednesday.

For those who missed the opportunity to pre-purchase and get early access to the demo, you won’t have to wait long – Left 4 Dead 2 hits the stores on November 17th.